Lake level still rising

Don’t start building an ark just yet.
While water levels on Rainy Lake currently are sitting above the International Rainy Lake Board of Control’s rule curve at the moment, it remains to be seen whether these high levels will stick around for the summer.

“Rainy Lake is definitely higher than the IRLBC would prefer,” interim co-chair Rick Walden said in an e-mail.
As of May 28, Rainy Lake was at 1,108.3 feet—9.3 inches above the upper rule curve but just 2.4 inches above the maximum URC level in July, Walden noted.
He added with inflow at about 3,500 cubic feet per second larger than the outflow, the lake level is still rising.
“While it remains to be seen how high Rainy Lake will rise this year, the current level, at only 2.4 inches above a normally-acceptable summer level, is not regarded by the board as a ‘flood’ level,” Walden said.
“How much longer the level rises, and how high it gets, is dependent on rainfall,” he stressed.
“We could easily end up with lake levels as high, or higher, than those of 2008. However, it should not be assumed that this will be the case this summer.
“While the level is currently high, and is likely to be for a while yet, a return to better weather would easily result in quite acceptable levels in the summer months,” Walden remarked.
This past winter’s weather, including a record snowfall in March, is one of the factors behind why the water levels are high.
“Since late April, the Rainy-Namakan basin has experienced three periods of well above normal rainfall which, combined with the above normal snowmelt run-off, has resulted in the current high lake level,” Walden explained.
“The fact that the rainfall has been fairly intense at times, instead of more evenly distributed, and the fact that the weather has been cool and cloudy, has also meant that more of the rainfall has run off into the lake and the basin hasn’t had a chance to dry out as much as it would under warmer, sunnier conditions.”
Lake levels will continue to rise, he added, until inflow and outflow are equal—something that is mainly subject to the continued amount of precipitation.
As of Thursday, 14 of the 15 gates were open at the dam here and water was being passed through both powerhouses, Walden said, with the final gate expected to be opened once it is effective to do so.
“It is anticipated that the final gate will be opened soon, although the lake level is still about 3.5 inches below the level at which the IJC order requires all gates to be open,” he noted.
“It is not effective to open gates faster than they have been due to the restriction in the upper river at the Ranier rapids,” Walden stressed.
“Larger amounts of water simply can’t pass through this restriction until the lake level is higher, so opening more gates sooner simply draws down the level of the river at the dam, resulting in less depth, or “head,” to push water through the sluices that are open.”
While some may suggest a solution to high water levels is drawing the level of Rainy Lake lower over the winter, Walden pointed to the IRLBC/IRRWPB Spring, 2009 report to the IJC, where in section 2.2 this proposal is addressed “in the context of the 2008 event and presents modelling results which show that this is simply not effective.”
Walden advised property owners to keep updated on the water level conditions, and take precautions for protecting shorefronts and docks.
Regularly updated water levels for Rainy Lake, and other information, can be found online at www.ijc.org, where a link to the “Rainy Lake Board of Control” can be found under the “Boards” tab.